An electromagnetic valve has a valve member driven by a solenoid device. JP 4093092 B describes an oil-pressure control valve used for an automatic shift as the electromagnetic valve. The solenoid device includes a plunger driven in an axial direction by magnetism, and an opposite wall arranged to oppose the plunger on one side in the axial direction. A volume variable chamber is defined between the plunger and the opposite wall. A volume of the volume variable chamber is changed by movement of the plunger. The opposite wall has a respiratory pore that causes the volume variable chamber to communicate with exterior space. When the plunger reciprocates in the axial direction, fluid flows out of the volume variable chamber through the respiratory pore and flows into the volume variable chamber through the respiratory pore as respiration.
However, a foreign object may be able to enter the solenoid device from the respiratory pore. If the solenoid device is used in oil as a part of oil-pressure control valve, a foreign object such as metal wear powder contained in oil may flow into the volume variable chamber by the respiration. If the metal wear powder adheres to the plunger, the plunger may not be able to properly slide and move.